@@ -128,5 +128,8 @@ endif
# Use '=' instead of ':=' to avoid $(shell ...) evaluation when cleaning
header-test-y = $(filter-out $(no-header-test), $(all-uapi-headers))
-# Use '=' instead of ':=' to avoid $(shell ...) evaluation when building
-clean-dirs = $(shell cd $(obj) 2>/dev/null && find * -maxdepth 0 -type d)
+# Use '=' instead of ':=' to avoid $(wildcard ...) evaluation when building
+#
+# For GNU Make 4.2.1, $(wildcard $(obj)/*/) matches to not only directories
+# but also regular files. Use $(filter %/, ...) just in case.
+clean-dirs = $(patsubst $(obj)/%/,%,$(filter %/, $(wildcard $(obj)/*/)))
Since commit b91976b7c0e3 ("kbuild: compile-test UAPI headers to ensure they are self-contained"), 'make clean' in a row for the separate output directory emits a warning. $ make -s O=foo allmodconfig; cd foo; make usr/; make clean; make clean [ snip ] CLEAN . CLEAN usr/include/asm usr/include/asm-generic usr/include/drm usr/include/linux usr/include/misc usr/include/mtd usr/include/rdma usr/include/scsi usr/include/sound usr/include/video usr/include/xen CLEAN usr CLEAN arch/x86/tools CLEAN .tmp_versions find: ‘*’: No such file or directory find: ‘*’: No such file or directory In the second 'make clean', $(objtree)/usr/include exists, but it contains nothing, then the 'find' command warns 'No such file or directory'. I replaced the nasty 'find' with $(wildcard ...). [Note] I wish I could write the code more simply, like this: clean-dirs = $(patsubst $(obj)/%/,%,$(wildcard $(obj)/*/)) I did not do that due to the bug of GNU Make <= 4.2.1 $(wildcard $(obj)/*/) should match to only directories since it has a trailing slash, but actually matches to regular files too. This bug was fixed by: | commit b7acb10e86dc8f5fdf2a2bbd87e1059c315e31d6 | Author: spagoveanu@gmail.com <spagoveanu@gmail.com> | Date: Wed Jun 20 02:03:48 2018 +0300 | | * src/dir.c: Preserve glob d_type field For GNU Make <= 4.2.1, clean-dirs would end up with containing 'usr/include/Makefile'. This would be harmless because Makefile.clean would search for the non-existing 'usr/include/usr/include/Makefile', then it would be filtered out by $(wildcard ...). However, I'd rather try my best to avoid buggy code. Reported-by: Arnd Bergmann <arnd@arndb.de> Fixes: b91976b7c0e3 ("kbuild: compile-test UAPI headers to ensure they are self-contained") Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> --- usr/include/Makefile | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)